The invention relates to a radiation apparatus comprising an element which is to be positioned with respect to an object. The element to be positioned is supported by a balanced suspension system comprising a counterweight.
Such an apparatus which comprises a gamma camera as a detector element is known from U.S. Pat. No. 4,057,726. The gamma camera included in the apparatus described therein is rotatable with respect to an isocentric axis of a patient. It is usually desirable that the gamma camera also be radially movable with respect to the isocentric axis. Because a gamma camera in combination with a collimator coupled thereto is a comparatively heavy element, it is suspended in a balanced manner by means of a counterweight. In practice, measurements are often impeded by the counterweight, which necessarily also rotates about the patient. Apart from the necessarily heavy construction, this drawback is even greater when an apparatus is to be constructed so that all parts of a patient can be reached thereby.